RAM memory not in dual channel, why?

My system is one month old, or something. I assembled it together with a friend. Since 1st day, CPU-Z does not report dual channel with my DDR3 Corsair Vengeance LP CML8GX3M2A1333C9 8GB ( 2X4GB ) 1333MHz. The sticks are in the slots the mobo manual recommends (A2 B2).

In the BIOS, I could not find the information if they're in single or dual channel.

My chipset and mobo drivers are all up to date.

Edit: Solved (by myself) . All I had to do was uninstall an re-install a newer version of cpu-z. I'm a hero.